The present invention relates to an optical information processing apparatus, for example, an optical disc device or the like, and more particularly to an optical information processing apparatus using a guide element.
An optical information processing apparatus using a guide element is described in JP-A-2-7238. In this type of optical information processing apparatus, an incident light coupling section in the guide element is split in a direction parallel to the optical axis of guided light.
When the size of a portion effective to excite guided light in the incident light coupling section is large, the tolerance of an incident angle of light which provides a suitable incidence efficiency becomes small, thereby presenting a problem that the mounting thereof cannot be easily adjusted.
On the other hand, when the size of the portion effective to excite guided light in the incident light coupling portion is small, a problem is also encountered that light incident on the incident light coupling section is not easily positioned.
Further, if the incident light coupling section is not split in a direction which intersects the optical axis of guided light, a sufficiently high incidence efficiency cannot be achieved.
As described above, it is quite difficult to improve the reliability of optics using such an incident light coupling section, from the fact that the mounting adjustment is not so easy and that the incidence efficiency is not sufficiently high, thereby presenting a problem that the reliability as the whole optical information processing apparatus cannot either be improved sufficiently.